1. Field of the Invention
The present invention relates to a semiconductor manufacturing apparatus and a manufacturing method of a semiconductor device.
2. Description of Related Art
Manufacturing methods of a semiconductor device generally include a wafer process in which a semiconductor wafer is processed, an assembly process and an inspection process. Japanese Laid Open Patent Application (JP-A-Heisei, 7-37870) and Japanese Laid Open Patent Application (JP-A-Heisei, 10-144495) disclose semiconductor manufacturing apparatus used in such wafer process.
FIG. 1 shows the semiconductor manufacturing apparatus 101 disclosed in Japanese Laid Open Patent Application (JP-A-Heisei, 7-37870). The semiconductor manufacturing apparatus 101 is used to remove resist from a wafer 127. The semiconductor manufacturing apparatus 101 includes a bell jar 102, a gas supplier 103, a vacuum chamber 104, a first electrode 106, a second electrode 111, a heater 114 and a conductive member 120. The bell jar 102 is made of quartz. The gas supplier 103 is connected to a top of the bell jar 102. A bottom of the bell jar 102 forms a flange. The bottom of the bell jar 102 is joined to a ceiling of the vacuum chamber 104. A shield electrode 112 forms a part of the ceiling of the vacuum chamber 104. The shield electrode 112 has holes 113 connecting inside of the bell jar 102 to inside of the vacuum chamber 104. The shield electrode 112 is grounded. The first electrode 106 and the second electrode 111 are placed outside of the bell jar 102. The conductive member 120 connects the first electrode 106 to a radio frequency power supply 118. The second electrode 111 is grounded. The heater 114 is placed in the vacuum chamber 104 and heats the wafer 127. A vacuum pump (not shown) connected to the vacuum chamber 104 exhausts the vacuum chamber 104 and the bell jar 102. The gas supplier 103 supplies oxygen gas 121 into the bell jar 102. The radio frequency power supply 118 supplies radio frequency power to the first electrode 106 via the conductive member 120 and then energizes the oxygen gas 121 to form plasma 122 in the bell jar 102. The plasma 122 contains oxygen molecules, oxygen atoms, oxygen ions and electrons. Neutral active species 123 of the plasma 122 enter the vacuum chamber 104 through the holes 113 and reacts with the resist on the wafer 127. Due to the reaction, the resist is removed from the wafer 127. Gas generated by the reaction is exhausted from the vacuum chamber 104 by the vacuum pump.
The present inventor has discovered that when the vacuum pump exhausts the vacuum chamber and bell jar 102, pressure difference is generated between inside and outside of the bell jar 102. Due to the pressure difference, the bell jar 102 is pressed onto the vacuum chamber 104. When an O ring seals between the bell jar 102 and the ceiling of the vacuum chamber 104, the O ring deforms and the bell jar 102 moves toward the vacuum chamber 104. When the first electrode 106 is fixed to the bell jar 102 and the conductive member 120 connecting the first electrode 106 to the radio frequency power supply 118 is a rigid body, due to repeated generation of the pressure difference, repeated load is applied to the bell jar 102 and the first electrode 106. The repeated load may destroy the bell jar 102 and the first electrode 106.